• 3-minute read
• 30th August 2023

What Is an Oxford Comma?

The Oxford comma, otherwise known as the serial comma, may be one of the most intensely debated punctuation marks in English. Even if you prefer not to use the Oxford comma, learning about its history and the rules (and sometimes even legal cases) surrounding it can be fascinating. In this post, we’ll discuss this somewhat controversial punctuation mark and include practical example sentences to illustrate our main points. Keep reading to learn about all things Oxford comma.

How to Use an Oxford Comma

The Oxford comma is placed before the coordinating conjunction (usually and or or) in a list of three or more items. The comma clarifies the separation between the final two items in the list, especially when they are closely related or their placement could cause confusion. For example:

With the Oxford comma, it’s clear in the first example that the speaker had dinner with their parents and two other individuals, Glenn and Janet. Without that comma, the sentence could be interpreted to mean that Glenn and Janet are the names of the speaker’s parents. In the second example, without the Oxford comma, it would not be clear whether the speaker’s best friends are their sister and brother or entirely different people.

However, the Oxford comma isn’t always strictly required for clarity. In the following example, it’s evident – with or without the final comma – that the grocery list consists of four different types of fruits:

Now for some historical context: The Oxford comma is said to be named for Horace Hart, who, from 1893 to 1915, was the printer and controller of the Oxford University Press, which traditionally advocated the use of the comma. He also wrote Hart’s Rules for Compositors and Readers in 1905 as a style guide for the employees of the press.

The Oxford Comma Debate

Some style guides, such as The Chicago Manual of Style, strongly advocate the use of the Oxford comma. The rationale for the comma’s consistent use is that it adds structure and prevents potential confusion (sometimes, omitting the Oxford comma can even have legal ramifications).

On the other side of the debate, those who prefer omitting the Oxford comma argue that doing so leads to simplicity and a cleaner visual appearance in writing. The suggestion is that the Oxford comma may be redundant when a conjunction is present, especially in simpler lists.

Sometimes, whether to use an Oxford comma is influenced by region. In general, American English tends to use the comma more frequently, and many American style guides recommend its consistent use. In British English, the Oxford comma is more often seen as optional, to be used when it enhances clarity.

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